272 Molecular Motion in Living Bodies. 



healthy cells, and I think it is exhibited in many of the condi- 

 tions under which the protoplasm of plants is engaged in forming 

 new organs, as well as in other cases in which previously 

 existing forms are being taken to pieces. In a physical point 

 of view, all that is required is the presence of molecules of the 

 ricrht size, in proportion to their weight, in a fluid of suitable 

 density, and not too viscid. 



The higher the power employed, the more extensively 

 this kind of motion can be traced. With my ^th I 

 have seen it well displayed in extremely minute vacuoles of 

 ciliated infusoria, and recently was much struck with it in blood 

 corpuscles taken from the gills of tadpoles in an early stage. I 

 believe I am right in stating that true blood corpuscles result 

 from embryonic or primary cells, differing considerably from 

 perfect blood corpuscles either white or red. In my tadpole 

 babies the particles circulating through 

 fic: 2. the gills in close, chain-like array, pre- 

 sented, when immersed in water, instead 

 1000 of the characteristic reptilian form, the 

 appearance of Fig. 2, and all the little 

 particles represented by the engraver's 

 dots, were in strong molecular motion, 

 which I presume to be connected with the process of develop- 

 ment. White nucleated corpuscles are gradually formed, giving 

 rise, in their turn, to tho red. 



The molecular motions must tend in living vessels, as they 

 do in pails or jugs, to prevent a fluid from clearing by the sink- 

 ing down of small suspended matters. They must also promote 

 any chemical and physical action between the fluid and the 

 particles which are continually rubbing themselves against it, 

 and they may thus perform an important function in the pro- 

 cesses both of vital construction and decay. 



I uppend to these brief notes a few extracts frpin two very 

 important papers by Professor Lionel Beale, which appeared in 

 the January and April numbers (1864) of the Quarterly Journal 

 of Microscopic Science : — 



MINUTE PARTICLES OP GERMINAL MATTER IN THE BLOOD. 



"In the blood of man and the higher animals a great num- 

 ber of minute particles, of tho same general appearance and 

 refractive power as the matter of which tho white blood cor- 

 puscles are composed, may be demonstrated. Some of theso 

 particles probably,, under certain conditions, grow into ordinary 

 white corpuscles, while others, after increasing to a certain size, 

 become red blood corpuscles.*" Dr. Beale adds that both 



* Quarterly Journal of Microscopic Science, April, 1864, page 48. 



